Patent GB-841490-A (GB)
Title: Improvements in or relating to telephone installation circuit arrangements for crossed-coil coordinate selectors having two coupling stages
IPC: H04Q3/00
Filed: 1957-07-10
Abstract: 841,490. Automatic exchange systems. SIEMENS & HALSKE A.G. July 10, 1957 [July 17, 1956], No. 21898/57. Class 40 (4). A group selector consists of a tandem arrangement of two crossed coil co-ordinate switches, i.e. switches comprising sets of perpendicularlyarranged coils having at their crossing-points, contacts made of magnetic material which are closed when the two coils associated with the contacts are energized. Once closed the contacts may be held closed by the energization of a third coil. The selector has ten inlets E1 . . . E10 each having access over the first of the switches to nineteen intermediate lines ZL1 ... ZL19 forming inlets to the second switch, each intermediate line having access therethrough to one line in each outgoing direction, e.g. ZL1 has access to outgoing lines (such as VL1 ... VL19 in direction VR10) in each of the directions VR1 ... 10. Each incoming line has access over one set of contacts of the first switch to a control circuit which receives the digit indicative of the outgoing direction and energizes a coil of the second switch associated with that direction, whilst at the same time coils of the second switch associated with free intermediate lines are energized to connect up outgoing lines in the required direction to the said free intermediate lines so allowing these outgoing lines to be tested and a connection to be set up accordingly. An incoming calling line El of a set E1 . . . 10 has earth on one or other of its speech conductors 9, 10 which operates relay P1 of a set of relays P1 . . . P10 and relay Ar follows. When the incoming line or an incoming line associated with a previous stage is connected to a register +ve potential is applied to wire 17, Fig. 2, and this operates R and P1 is thereby released. When a digit is received in the digit repeater circuit of Fig. 2 it is recorded on combinations of relays A ... D of which at least one of A and C is always operated. One of relays P1... P10, say P1, indicative of the calling line, thus operates over one of the speaking wires and locks, and S1 follows to disable the other relays of the chain. Vertical coil Y associated with the control circuit and horizontal coil X1 associated with the incoming line then operate to close cross-point contacts kl connecting the incoming line to the control circuit. Digits are now transferred from the repeater to the storage relays A1 . . . D1 of the control circuit as follows : one or both of relay A1, C1 operate over the speech wires and rectifiers Gu1 Gu3, Fig. 2. This brings up F and G. Operation of A1, C1 and F rearrange the circuit of a previously-charged condenser Ko1, so that the lower ends of windings B1(i), D1(i) are brought to a potential below that of the - ve pole of the battery. Relays B1 D1 are thus permitted to operate over the speech wires and rectifiers Gu2, Gu4 if corresponding registrations have been made in the digit repeater circuit, Fig. 2. Relays A1 . . . D1 lock up over their windings (ii). Relay G brings up Fh and energizes vertical coil Yr associated with the outgoing side of the setting up circuit. Fh releases P1 and energizes horizontal coil XrlO (say) associated with the digit received on A1 . . . D1. Yr and Xr10 thereby close contact kr10 (one such kr contact is associated with each outgoing direction) to short-circuit G which releases slowly. During the operation of relay G, relays P1 . . . P10 are connected to the test wires of interstage links ZL1 . . . ZL10. If, say, the first and last of these is free, P1, P10 operate to negative potential on wire 110, and bring up corresponding vertical coils Ya1 Ya10 so that with Xr10 operated these links are end-connected to a trunk in the direction designated by Xr10. When G releases P1 . . . P10 fall back but then immediately test the outgoing trunks connected to the interstage links over wires 132, 138. These are connected up by H1 which operates when G releases, H2 operating subsequently to release H1. This completes the energization over lead 125, Figs. 4 and 6, for a chain circuit involving contacts of relays P1 ... P10 and vertical coils Yv1 . . . Yv10. The first Yv coil, say Yv1, corresponding to an operated P relay, is thus energized. Thus with coil X1 operated, energized cross-point contacts kv1/1 are closed connecting the horizontals corresponding to inlet E1 with the interstage link ZL1 the latter being connected at cross point ka 1/10 to outgoing trunk VL1 in direction VR10. Relay Ph now operates over lead 150 to - ve in the outgoing trunk test wire and short-circuits its lower winding, thereby busying both link ZL1 and the outgoing trunk. Ph applies positive potential to both speech wires to bring up Zh in the digit repeater as a signal to set up the next digit. Release of G releases R followed by H 2 . The latter removes a short-circuit from C11(i) which operates to switch through the inlet E1 which is thereby disconnected from the control circuit. Relay C11 is held over coil C11 (ii) and the cross-point holding coils Ha1, Hv1 are energized by +ve over lead 17 of E1 C1 releases Ph which releases the control circuit. If all of links ZL1 ... 10 are busy so that none of P1... P10 operate, relay F is short-circuited and releases, thereby bringing up U which prepares vertical coils Ya11 . . . Ya19 and releases Xr10. With the short-circuit at kr10 removed G re-operates and releases H2. F re-operates, followed by Xr10. With U operated tests proceed in substantially the same manner as before on links ZL11 ... 19 and connection is made via one of them. If between the testing of a free outlet and switching through the outlet is seized by another selector Ph fails to operate and switch-through is prevented. When R, S1 fall away a further attempt is made to connect to a different outlet in the wanted direction. All trunks busy.-If all the interstage links ZL1 . . . ZL19 are busy, or if all the outlets in the required direction are busy then relays P1 ... P10 fail to respond on the first test over links ZL1 ... ZL10 and P1 . . . P9 fail on the second test over links ZL11 . . . ZL19. In this case P10 is operated over its winding (ii), thereby applying positive potential via rectifier Gk to overflow meters VR1 . . . VR0 associated with the different traffic directions and connected up over a contact tree of relays A1 . . . D1 This positive potential is also applied over rectifier Gc and lead 210 to operate C11(i), Fig. 3. Ph not having operated, Zh fails to operate in the digit repeater and this enables busy tone to be reverted. Operation of C11 effects release of the setting device.